The present invention relates generally to a method and apparatus for an improved electric fence wire construction for use in intensive grazing, pet control, and other electric fence applications. Particularly, the present invention relates to an improved electrified fence wire construction useful for permanent or temporary fencing in conjunction with intensive grazing of livestock such as cattle, sheep, pigs, etc. The improved fence wire comprises a wire core or cores which support a strip of metallic foil which is highly visible to animals, and also presents an enhanced surface area for conducting electricity.
An important aspect of livestock farming is the ability to provide high quality feed to the animals at all times of the year at the lowest possible price. Two distinct methods are typically used: (a) year-round confinement feeding, and (b) pasturing. Generally, two types of feed are used to maintain the animals in good condition. In the winter, the animals are usually fed stored forage that has been machine harvested during the summer and fall months. Termed silage, this is generally supplemented with grains and vitamins. This is an expensive method of feeding the animals, which has the unwanted result of increasing the farmer's production cost. The second type of feed is associated with the pasturing method. Animals are turned out to pasture during the spring, summer and fall months when pasture plants are creating enough quality forage for the animals to subsist. This is the lowest-cost method of feeding animals, but it cannot be maintained year-round in most areas of the country. Permanent pastures also become run-down, as noted below.
In the past, low-quality, intermittent forage was produced in a continuous-use pasture because of poor grazing management. Typically, conventional grazing is characterized by setting a group of animals loose in a relatively large area to forage the available plants growing within the pasture at random. The animals selectively graze, meaning they eat only what they like, thus changing the distribution of plants in the pasture. The result of this selective foraging is a pasture where the clover and grasses have been selectively and separately cut low, while unpalatable species such as weeds continue growing unimpeded. The weeds then have a competitive advantage over the more desirable species, such as clovers and grasses, and after several years of grazing in this manner a pasture can be depleted of desirable species and overrun with undesirable weeds. This run-down state is directly attributable to infrequent or continuously understocked grazing.
On the other hand, intensive grazing is the method of pasture management wherein larger numbers of animals are grazed together in a small area, thereby raising the density of the animals to a point where the entire pasture is foraged evenly and completely. This does not allow the weeds to develop any competitive advantages because they are eaten after the more desirable species are, thus keeping all the plants at the same growth level. The area foraged will not support the livestock for more than a small amount of time, but this is intentional.
Intensive grazing is accomplished by subdividing a large pasture area into smaller areas called paddocks, and retaining the animals within a particular paddock for a short amount of time, usually from twelve to no longer than forty-eight hours. The animals are then moved to a new paddock, resting the plants within the newly-foraged paddock for an amount of time sufficient to allow the plants to generate substantial new growth. It is critically important that some minimum rest time for the newly foraged paddock is maintained so that new leaf formation can occur. This allows the plants to recover sufficiently so that they are able to grow new leaves and stems for the next round of grazing. In order to allow the desired recovery of the plants, a temporary back fence is located where the old temporary front fence of the prior paddock was. This prevents the animals from returning to the old paddock and foraging the new growth. Farm animals are apt to do so because new growth is more palatable to them. The intensive grazing method has shown itself to be a vastly superior method of grazing farm animals over the conventional technique. Animal production costs are lowered by, first, less dependence on expensive silage feed, and, second, by enhancing the productivity of the pasture. It has been documented that, by resting pasture plants and not allowing reforaging in a short time, the pasture becomes much more productive as a whole. The method is described in detail in Greener Pastures on Your Side of the Fence, Murphy, B., 1987, Capital City Press, Montpelier, Vt.
A key to the success of intensive grazing is the ability to create secure new paddocks on a flexible, as-needed basis. One reason for this needed flexibility is that, as environmental conditions change, the rest times for the paddocks vary. For instance, as rainfall and sunlight decrease in the latter part of the summer, plant growth slows, mandating longer rest periods. Another reason is that subdividing pasture land into many paddocks creates a need for a temporary fencing system. This is so because if all permanent fencing was used, the cost would be very high.
The temporary fence used should take into consideration the poor vision of many larger animals, such as horses and cattle. There are several criteria a livestock fence should satisfy to be effective. Visibility can be enhanced by attaching flags or tape to the wire. A temporary movable fence for enclosing paddocks should be both visible to the animals, and also possess a strong deterrent value to contact by both those animals inside the fence, and predators outside the fence. Provision for a deterrent is normally made by electrifying the fence, either continuously or at short intermittent intervals. A commonly used electric fence wire is made of galvanized high-tensile steel wire. While strong and a good transmitter of electricity, it is not a good choice for a temporary fence due to its low visibility, and difficulty of handling.
Temporary flexible electric fencing is not a new idea. There exist several different types of flexible electric fencing commonly used today. See, e.g., Intensive Grazing Management: Forage, Animals, Men, Profits, Smith, B., et al., p. 178, 1986, Yu Luen Offset Printing Factory, Ltd., Hong Kong. For instance, polywire is a temporary fence twine made up of strands of polymer twine interwoven with several filaments of stainless steel for conducting the electricity. Polywire is flexible, and therefore easily rewound. Electric current can be applied to the polywire sufficient to provide a deterrent to both livestock and predators. Another form of temporary fence wire is called polytape. Polytape is similar to polywire in that both are made from an ultraviolet resistant plastic interwoven with thin strands of stainless steel wire, and are very flexible. Polytape, because it is wider and tends to flutter in the wind, is more visible than polywire. However, both polytape and polywire have the disadvantage of having high resistance values; therefore, their use is restricted to under 1,000 feet for three strand construction and under 2,000 feet for six strand constructions. Polywire and polytape are also physically weak, and they cannot be uniformly stretched without some risk of breaking the stainless steel filaments that are embedded within the wire or tape. Thus, they cannot be used as permanent perimeter electric fence wire. There is a need for an improved multi-purpose fence wire useful for intensive grazing and capable of service as both permanent and temporary electric fence wire.